Cisco Asr 1000 Series Aggregation Services Routers Sip And Spa Software Configuration Guide, Cisco Ios - Cisco ASR 1000 Series Software Configuration Manual

Serial Lines: Troubleshooting Serial Line Input Errors
Table 30: Serial Lines: Troubleshooting Serial Line Input Errors
Input Error Type(Field Name)
CRC errors (CRC)

Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide, Cisco IOS

XE Everest 16.5
334
Possible Problem
CRC errors occur when the CRC
calculation does not pass
(indicating that data is corrupted)
for one of the following reasons:
• The serial line is noisy.
• The serial cable is too long,
or the cable from the
CSU/DSU to the router is not
shielded.
• Serial clock transmit external
(SCTE) mode is not enabled
on the DSU.
• The CSU line clock is
incorrectly configured.
• A ones density problem has
occurred on the T1 link
(incorrect framing or coding
specification).
Troubleshooting the Serial SPAs
Solution
1 Ensure that the line is clean
enough for transmission
requirements. Shield the cable,
if necessary.
2 Make sure that the cable is
within the recommended length
(no more than 50 feet [15.24
meters], or 25 feet [7.62
meters] for a T1 link).
3 Ensure that all devices are
properly configured for a
common line clock. Set SCTE
on the local and remote DSU.
If your CSU/DSU does not
support SCTE, see the to invert
the transmit clock signal.
4 Make certain that the local and
remote CSU/DSU are
configured for the same
framing and coding scheme as
that used by the leased-line or
other carrier service (for
example, Extended Superframe
Format/binary eight-zero
substitution [ESF/B8ZS]).
5 Contact your leased-line or
other carrier service, and have
it perform integrity tests on the
line.
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